"Our findings are consistent with the idea that gestational environmental chemical exposures can contribute to the development of health and disease," said lead author Michele La Merrill, an assistant professor of environmental toxicology at University of California, Davis.

The study found that women whose mothers smoked while pregnant were two to three times as likely to be diabetic as adults. Dads who smoked while their wives were pregnant also contributed to an increased diabetes risk for their child.

The study analysed data from 1,800 daughters of women who had participated in the Child Health and Development Studies, an ongoing project of the Public Health Institute.In previous studies, foetal exposure to cigarette smoke has also been linked to higher rates of obesity and low birth weight.

This study found that birth weight had no effect on daughters of smoking parents developing diabetes."We found that smoking of parents is by itself a risk factor for diabetes, independent of obesity or birth weight," said La Merrill."

If a parent smokes, you're not protected from diabetes just because you're lean," the researcher added.The findings were published in the Journal of Developmental Origins of Health and Disease.